Marie Curie's daughter spied on by UK intelligence

Following in the footsteps of her parents, Irene Joliot-Curie won the Nobel Prize for chemistry in 1935, together with husband Frederic. The pair had been instrumental in the discovery of the neutron.

However, two years later, British intelligence officers opened a file on the couple. Irene came under scrutiny for her communist activity. The documents note that Irene joined France's communist anti-war committee in 1938.

The distinguished chemist had formerly been involved in organising armaments for the Republicans during the Spanish Civil War. She officially joined the communist party in 1944.

The file was closed in 1950, and Irene Joliot-Curie died from leukemia in March 1956. Her husband passed away two years later. The couple were never permanently based in the UK.

Britain's National Archives reveal that tens of thousands of people were under surveillance due to their alleged political beliefs. Other newly released materials show that Britain's MI5 agreed to investigate film legend Charlie Chaplin, following a request from the FBI. Nevertheless, the actor was eventually knighted by Queen Elizabeth in 1975, two years before his death in 1977.

Irene Joliot-Curie and her husband Frederic in 1934. Photo: Wikimedia Commons.